[PATCH 41/58] LSM: Use lsm_context in dentry_init_security hooks

[Casey Schaufler]

From: Casey Schaufler <cschaufler at schaufler-ca.com>

Convert SELinux to use the lsm_context structure
instead of a context/secid pair. There is some scaffolding involved
that will be removed when the related data is updated.

Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
---
 include/linux/lsm_hooks.h |  7 +++----
 security/security.c       | 10 ++++++++--
 security/selinux/hooks.c  |  8 ++++----
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index eda0a1bcdf07..d4ace7af4950 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -165,8 +165,7 @@
  *	@dentry dentry to use in calculating the context.
  *	@mode mode used to determine resource type.
  *	@name name of the last path component used to create file
- *	@ctx pointer to place the pointer to the resulting context in.
- *	@ctxlen point to place the length of the resulting context.
+ *	@cp pointer to place the pointer to the resulting context in.
  * @dentry_create_files_as:
  *	Compute a context for a dentry as the inode is not yet available
  *	and set that context in passed in creds so that new files are
@@ -1492,8 +1491,8 @@ union security_list_options {
 	int (*sb_add_mnt_opt)(const char *option, const char *val, int len,
 			      void **mnt_opts);
 	int (*dentry_init_security)(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen);
+					const struct qstr *name,
+					struct lsm_context *cp);
 	int (*dentry_create_files_as)(struct dentry *dentry, int mode,
 					struct qstr *name,
 					const struct cred *old,
diff --git a/security/security.c b/security/security.c
index 4f443dd481bd..c04b334370a5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1017,8 +1017,14 @@ int security_dentry_init_security(struct dentry *dentry, int mode,
 					const struct qstr *name, void **ctx,
 					u32 *ctxlen)
 {
-	return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
-				name, ctx, ctxlen);
+	struct lsm_context lc = { .context = NULL, .len = 0, };
+	int rc;
+
+	rc = call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
+				name, &lc);
+	*ctx = (void *)lc.context;
+	*ctxlen = lc.len;
+	return rc;
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 633d62b97e90..fe09905d013c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2813,8 +2813,8 @@ static void selinux_inode_free_security(struct inode *inode)
 }
 
 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
-					const struct qstr *name, void **ctx,
-					u32 *ctxlen)
+					const struct qstr *name,
+					struct lsm_context *cp)
 {
 	u32 newsid;
 	int rc;
@@ -2826,8 +2826,8 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
 	if (rc)
 		return rc;
 
-	return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
-				       ctxlen);
+	return security_sid_to_context(&selinux_state, newsid, &cp->context,
+				       &cp->len);
 }
 
 static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,
-- 
2.19.1